Abstract:The gold grade of a fine-grained complex refractory gold ore is 2.15 g/t, which is the main recovered element. The gold in the ore is mainly in the form of sulfide coated gold, accounting for 84.51%, and bare gold is less, accounting for only 4.23%. The metallic minerals in the ore are mainly pyrite, the non-metallic minerals are mainly quartz, followed by dolomite and Muscovite. According to the properties of the ore, combined with the on-site flotation process and chemical system, chemical optimization test and grinding optimization test were carried out. The best chemical roughing system was as follows: The dosage of sodium carbonate is 400 g/t, sodium sulfide is 12 g/t, copper sulfate is 100 g/t, Jingjiang MA is 200 g/t, BKG721 is 28 g/t. On the basis of the best reagent system, the comparison test between the process of "one-stage grinding, one-stage sorting" and the process of two-stage grinding, two-stage sorting and medium-ore regrinding is carried out. The results show that the process of two-stage grinding, two-stage sorting and medium-ore regrinding is more ideal. That is, the fineness of the first stage grinding is 70% of -0.074mm, the second stage grinding is 87.7% of -0.045mm, and the middle ore regrinding is 94% of -0.038mm, and a gold concentrate with yield of 6.00%, gold grade of 31.37g /t and gold recovery rate of 87.35% can be obtained. Compared with the on-site production process, the overall recovery rate of gold was increased by 9.75 percentage points. The research results will provide a basis for field technical transformation.